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1.
采用溶剂热方法合成了沸石咪唑酯骨架结构材料Co-ZIF-9,并将其用于非均相催化氨硼烷水解放氢实验.结果表明:配位的Co-ZIF-9在室温下能够有效地催化氨硼烷放出氢气,且其催化活性远高于Co纳米粒子,Co-ZIF-9的多孔结构在催化中起了很大的作用.另外,Co-ZIF-9催化水解氨硼烷的活化能约为40.8 k J mol-1,低于多数用于该催化实验的其他催化剂,表明所合成的沸石咪唑酯骨架结构材料Co-ZIF-9具有优越的催化性能.  相似文献   

2.
采用Na H2PO2还原法首次将Ru和P负载于高孔隙率的金属有机骨架材料MIL-110(Al)上,得到新颖的金属-非金属双组份负载型催化剂Ru-P@MIL-110.通过一系列表征手段分析该催化剂的结构、粒径分布、元素组成及价态,并在室温下通过催化氨硼烷水解释氢实验研究其催化活性.结果表明,非金属P的加入能显著提高催化活性,Ru-P@MIL-110催化剂对氨硼烷的水解释氢有好的催化活性,其TOF值为8 646 m L H2·min-1(g catalyst)-1,活化能为42.2 k J·mol-1.经5次循环实验后,该催化剂仍保持结构稳定和高的可耐受性.  相似文献   

3.
沸石咪唑酯骨架-8(ZIF-8)材料,具有比表面积高、孔结构有序、结晶度及多金属位点高、热稳定性及化学稳定性强等优点,对水体污染物具有较强吸附作用.ZIF-8与其他材料复合产生的协同效应,使催化吸附作用更强,且对污染物更具针对性,在工业废水处理中具有应用前景.该文概述了ZIF-8及其复合材料制备和应用的研究进展,展望了ZIF-8复合材料未来可能的研究方向.  相似文献   

4.
采用浸渍还原法成功制备不同比例的双金属负载型催化剂Ru Co@UIO-66-NH_2,并用于室温催化氨硼烷水解产氢性能研究.通过一系列表征手段分析了该催化剂的结构、粒径分布、元素组成及价态,并在室温下通过催化氨硼烷水解释氢实验研究其催化活性.结果表明,非贵金属Co的加入能显著提高Ru的催化活性,Ru1Co1@UIO-66-NH_2催化剂表现出最高的催化活性,其TOF值为570. 8 mol H_2min~(-1)(mol Ru)~(-1),活化能为39. 2 k J mol~(-1).  相似文献   

5.
精确调节金属中心的协调环境,进一步最大化过渡金属催化剂的活性是电催化领域的迫切需求.以金属有机框架(MOFs)的沸石咪唑酯骨架结构材料ZIF-8为前驱体,通过高温碳热还原制备了多孔碳-铁(Fe/C)复合材料,并用于电化学催化合成氨.利用XRD,SEM等手段对其进行了表征,再在H型电解池中电解2 h测试其催化合成氨的性能.结果表明:在相对于可逆氢电极电势为-0.2 V下,氨产率达到38.2μg·h~(-1)·mg~(-1),法拉第效率(FE)达到2.06%,说明了ZIF-8衍生多孔碳-铁复合物具有明显的合成氨电催化性能.此外,在16 h耐久性测试与4次循环性测试后,该催化剂仍具有良好的合成氨催化活性.  相似文献   

6.
手性沸石材料近年来在对映选择性催化和分离方面越来越引起人们的关注,主要由于该类材料具有独特性能,如高表面积、迷人的结构和优秀的化学和热稳定性.研究合成了一种拥有一维螺旋10环通道的手性沸石开放骨架材料CoAPO-CJ40.使用CoAPO-CJ40作为固定相制备了涂层毛细管手性柱(2 m×75μm i.d.),用于气相色谱分离外消旋体、位置异构体和直链烷烃混合物.选用正十二烷作为分析物在120℃下测定了CoAPO-CJ40涂层柱的理论塔板数为2 665块/米.实验结果表明该手性柱对直链烷烃混合物和位置异构体有较好的选择分离能力,对外消旋化合物也有一定的手性识别能力.  相似文献   

7.
以高锰酸钾改性后的花生壳为原料,通过共沉淀法制备了磁性花生壳(PSK-Fe_3O_4)复合材料,并以其为载体制备了磁性花生壳负载钯催化剂(Pd/PSK-Fe_3O_4).以XRD、FT-IR、TEM、XPS、TG等表征手段对该催化剂进行了表征,并将其应用于催化氨硼烷水解释氢.结果表明:Pd/PSK-Fe_3O_4催化剂在催化氨硼烷水解反应中表现出较好的催化活性,其转换频率(TOF)为6.7 mol_(H2)·mol_(Pd)~(-1)·min~(-1),表观活化能(E_(app))为28.0 kJ mol~(-1).Pd/PSK-Fe_3O_4催化氨硼烷水解释氢反应对于催化剂浓度和氨硼烷浓度的反应级数分别为一级和零级.此外,循环实验表明该催化剂具有较好的循环稳定性.  相似文献   

8.
手性方酰氨基醇配体的设计合成   总被引:1,自引:1,他引:0  
方酸与不同烃基结构的醇反应生成相应的方酸二酯,继而与手性氨基醇作用合成了方酸C-3位含酯氧基的手性方酰氨基醇配体。手性方酰胺正丁脂经水解或与硫氢化钠作用分别得到C-3位含羟基和巯基的手性方酰氨基醇配体。上述新型配体与硼烷作用形成的手性E唑硼烷可用于前手性酮的不对称催化还原反应。所有新型配体的结构已被IR,^1H NMR,MS 和元素分析所确证。  相似文献   

9.
本文用Abinitio和CNDO/2法计算了硼烷B_6H_6~(2-),B_5H_9,B_6H_(10)和B_4H_(10)及其骨架和配位氢的电子结构。着重从硼烷骨架和配位氢相互作用观点讨论了硼烷的成键。指明了骨架B_n已完全确定了硼烷的成键轨道个数。  相似文献   

10.
报道了同时采用催化剂和限域基体对氨硼烷(BH3NH3)脱氢性能的影响.结果发现,非贵金属催化剂和孔状限域基体能显著改变氨硼烷的储氢性能.填充在介孔二氧化硅中含Co催化剂的氨硼烷在75℃或90℃能释放出4%或9%纯氢,进一步用锂修饰介孔二氧化硅可使氨硼烷脱氢速度更快,但产生氢气、氨气和二硼烷的混合气.氨硼烷热分解活化能的降低导致填充在介孔二氧化硅中含催化剂的氨硼烷具有较快的动力学和热力学行为.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

17.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

18.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
The non-orthogonal localized molecular orbital(NOLMO)is the most localized representation of electronic degrees of freedom.As such,NOLMOs are thus potentially the most efficient for linear scaling calculations of electronic structures for large systems.However,direct ab initio calculations with NOLMO have not been fully implemented and widely used,partly because of the slow convergence issue in the optimization of NOLMO.We devel-  相似文献   

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